Boost Converter 12V to 120V DC Step-Up Circuit

A Boost Converter circuit is made to raise the voltage from 12V to 120V DC, which is super important for adjusting voltage levels when we need to.

This circuit takes a 12V DC input and transforms it into a powerful 120V DC output making it really handy for times when we need a high voltage DC supply from lower voltage sources like batteries.

The output power of this DC-DC converter is approximately 100 watts.

The circuit has two main parts the first part works like a simple inverter and the second part has a rectifier and a filter.

The IC 555 timer is set up as an astable multivibrator running at a frequency of 100Hz and it connects to the clock input of a CMOS CD4013 chip, which is a dual Flip-Flop.

This circuit operates using a switching system that includes the IC 555 timer the CD 4013 flip-flop, power transistors and a step-up transformer to boost the voltage.

Circuit Working:

Parts List:

This Boost Converter 12V to 120V DC Step-Up Circuits working is mentioned below:

Oscillator Stage IC1 555 Timer:

The IC1 555 timer is arranged as an astable multivibrator.

This setup creates a clock pulse that controls how the flip-flop IC2 CD4013 works.

The speed of the oscillation depends on the resistors VR1 and R1 along with capacitor C1.

Flip-Flop CD4013 IC2:

The CD4013 flip-flop is used to cut the frequency from the IC1 555 timer in half.

This process produces alternating pulses that turn on the power transistors named Q1 and Q2.

Power Transistors MJ3001:

The transistors Q1 and Q2 act like electronic switches controlling the current that flows through the primary side of the transformer.

This creates an alternating magnetic field, which helps to produce a higher voltage in the transformers secondary side.

Step-Up Transformer:

The transformer 9-0-9V increases the voltage from about 12V AC to roughly 120V AC.

Rectification and Filtering:

The bridge rectifier D1 changes alternating current AC into direct current DC.

After this change capacitors C3 and C4 are used to smooth out the output providing a steady 120V DC.

Formulas with Calculations:

The below mentioned formulas with calculations can be used for better understanding of Boost Converter 12V to 120V DC Step-Up Circuit:

IC1 555 Timer Frequency Calculation:

The frequency of the astable multivibrator is given by:

f = 1.44 / ((VR1 + 2R1) * C1)

Substituting values:

f = 1.44 / ((100kΩ + 2 * 18kΩ) * 330nF)

f = 24.5 Hz

Flip-Flop Output Frequency:

Since the CD 4013 flip-flop divides the frequency by 2:

f_out = 24.5 / 2

f_out = 12.25 Hz

where,

• f_out is the output frequency of the CD4013 flip-flop in Hz
• f is the input frequency from the IC1 555 timer in Hz

Transformer Voltage Gain:

The voltage transformation is determined by the turns ratio:

V_secondary = V_primary * (N_secondary / N_primary)

Given that primary voltage is approximately 12V AC and the turns ratio is 1:10, we get:

V_secondary = 12V * 10

V_secondary = 120V AC

where,

• V_secondary is the output voltage from the transformer in volts
• V_primary is the input voltage to the transformer in volts
• N_secondary is the number of turns in the secondary winding of the transformer
• N_primary is the number of turns in the primary winding of the transformer

Output DC Voltage after Rectification:

The peak output voltage after rectification is:

V_DC = V_AC_peak – V_drop

• V_DC is the output DC voltage after rectification in volts
• V_AC_peak is the peak AC voltage from the transformer in volts
• V_drop is the voltage drop across the diodes in the bridge rectifier in volts

Peak AC Voltage Calculation:

V_AC_peak = V_AC_rms * sqrt(2)

• V_AC_peak is the peak voltage of the AC signal in volts
• V_AC_rms is the root mean square RMS voltage of the AC signal in volts
• sqrt(2) is the conversion factor from RMS to peak voltage approximately 1.414

How to Build:

To build a Boost Converter 12V to 120V DC Step-Up Circuit follow the below mentioned steps for connections:

• Gather all the components as mentioned in the above circuit diagram
• Connect pin 1 of IC1 555 to GND of the circuit
• Connect pin 2 of IC1 to pin 6 of IC1
• Connect pin 3 of IC1 to pin 3 of IC2 though resistor R4
• Connect pin 4 and pin 8 of IC1 to +12V DC supply
• Connect resistor VR1 between pin 7 of IC1 and positive supply of +12V
• Connect resistor R1 between pin 7 of IC1 and pin 6 of IC1
• Connect capacitor C1 between pin 2 and pin 6 of IC1 and GND
• Connect resistor R2 from pin 3 of IC1 and GND
• Connect positive of capacitor C2 to positive supply of +12V and negative of capacitor connect to GND
• Connect pin 1 of IC2 to the base of transistor Q1 through resistor R4
• Connect pin 4 ,6 and pin 7 of IC2 to GND
• Connect pin 2 and pin 5 of IC2 to base of transistor Q2 through resistor R5
• Connect pin 14 of IC2 to positive supply of +12V DC
• Connect the collector of transistor Q1 to primary of transformer
• Connect the emitter of transistor Q1 to emitter of transistor Q2
• Connect the primary center wire of transformer to positive supply of +12V DC
• Connect the collector of transistor Q2 to primary third wire of transformer
• Connect the secondary wires of transformer to both the end of bridge rectifier D1-D4 and and rest two end of bridge rectifier connect to 120V DC
• Connect capacitors C3 and C4 across the bridge rectifier output of the transformer

Conclusion:

This Boost Converter 12V to 120V DC Step-Up Circuit is a handy and effective circuit that increases low voltage DC to high voltage DC.

It features an 555 timer and a CD 4013 flip-flop that control power transistors, which then operate a step-up transformer.

The output is rectified and filtered to deliver a steady 120V DC.

This circuit is great for small power needs emergency lighting setups and portable high voltage gadgets.

References:

Stepping up from 12vdc to 100vdc/-100vdc